title: P2X7R/cryopyrin inflammasome axis inhibition reduces neuroinflammation after SAH.
abstract: Neuroinflammation contributes to the pathogenesis of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Cytotoxic events following SAH, such as extracellular accumulation of adenosine triphosphate (ATP), may activate the P2X purinoceptor 7 (P2X7R)/cryopyrin inflammasome axis, thus inducing the proinflammatory cytokine IL-1β/IL-18 secretion. We therefore hypothesized that inhibition of P2X7R/cryopyrin inflammasome axis would ameliorate neuroinflammation after SAH. In the present study, SAH was induced by the endovascular perforation in rats. Small interfering RNAs (siRNAs) of P2X7R or cryopyrin were administered intracerebroventricularly 24h before SAH. Brilliant blue G (BBG), a non-competitive antagonist of P2X7R, was administered intraperitoneally 30min following SAH. Post-assessments including SAH severity score, neurobehavioral test, brain water content, Western blot and immunofluorescence, were performed. Administration of P2X7R and cryopyrin siRNA as well as pharmacologic blockade of P2X7R by BBG ameliorated neurological deficits and brain edema at 24h following SAH. Inhibition of P2X7R/cryopyrin inflammasome axis suppressed caspase-1 activation, which subsequently decreased maturation of IL-1β/IL-18. To investigate the link between P2X7R and cryopyrin inflammasome in vivo, Benzoylbenzoyl-ATP (BzATP), a P2X7R agonist, was given to lipopolysaccharide (LPS) primed naive rats with scramble or cryopyrin siRNAs. In LPS-primed naive rats, BzATP induced caspase-1 activation and mature IL-1β release were neutralized by cryopyrin siRNA. Thus, the P2X7R/cryopyrin inflammasome axis may contribute to neuroinflammation via activation of caspase-1 and thereafter mature IL-1β/IL-18 production following SAH. Therapeutic interventions targeting P2X7R/cryopyrin pathway may be a novel approach to ameliorate EBI following SAH.
authors.affiliation: Department of Neurosurgery, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Chen
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Ma
authors.forename: Paul R
authors.initials: PR
authors.lastname: Krafft
authors.forename: Qin
authors.initials: Q
authors.lastname: Hu
authors.forename: William
authors.initials: W
authors.lastname: Rolland
authors.forename: Prativa
authors.initials: P
authors.lastname: Sherchan
authors.forename: Jianmin
authors.initials: J
authors.lastname: Zhang
authors.forename: Jiping
authors.initials: J
authors.lastname: Tang
authors.forename: John H
authors.initials: JH
authors.lastname: Zhang
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001929:Brain Edema / Q000209:etiology; D002352:Carrier Proteins; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004660:Encephalitis / Q000188:drug therapy* / Q000209:etiology*; D007276:Injections, Intraventricular; D008070:Lipopolysaccharides; D008297:Male; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000378:metabolism*; D012394:Rosaniline Dyes / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000188:drug therapy
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D008070:Lipopolysaccharides; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C573346:Nlrp3 protein, rat; D010975:Platelet Aggregation Inhibitors; D034741:RNA, Small Interfering; D018160:Receptors, Cytoplasmic and Nuclear; D058486:Receptors, Purinergic P2X7; D012394:Rosaniline Dyes; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate; C004692:coomassie Brilliant Blue
keywords: ANOVA; ASC; ATP; BBG; Benzoylbenzoyl-ATP; Brilliant blue G; BzATP; CNS; Cryopyrin; EBI; Early brain injury; Edema; IACUC; IL-1β; Inflammation; Institutional Animal Care and Use Committee; LPS; MPO; NF-κB; NLR; P2X purinoceptor 7; P2X7R; SAH; SD; Sprague–Dawley; Subarachnoid hemorrhage; TLR4; Toll-like receptor 4; adenosine triphosphate; analysis of variance; apoptosis-associated speck-like protein containing a CAED; central nervous system; early brain injury; interleukin-1β; lipopolysaccharide; myeloperoxidase; nuclear factor-kappa B; nucleotide-binding domain, leucine-rich repeat containing; siRNA; small interfering RNA; subarachnoid hemorrhage